Yeah, that's always the tricky part. Mostly they just want free games, so they can tell their friends they played a game before it came out.

We give out a few dozen copies to beta testers, and then we write down the names of the people who actually wrote something insightful, then use them on the next games. We did have a few pretty thoughtful testers.

As others have said, it shouldn't be find to hard people who want to beta test. The hard part is finding people who actually will beta test.

There's no way of knowing whether someone will give useful feedback or any feedback at all, but I found that having people complete a form will give you a general idea of how much they value their input and will pass it on to you. Good luck.